A large portion of the problems in the chemical process industry leading to premature metal component degradation is the result of the combined effects of corrosion and wear. Often, items of equipment which suffer such degradation are the most critical components of the system, e.g., pumps, valve parts, agitators, wear shields, elbows, fan blades, filters and rolls. White cast irons, high carbon high chromium irons and high carbon cobalt-base alloys have exhibited excellent wear resistance but very limited corrosion resistance. Stainless steels and various low-carbon nickel-base and cobalt-base alloys have provided excellent corrosion resistance to many aggressive environments but very little resistance to abrasion.
In U.S. patent application Ser. No. 07/984,709, filed Dec. 3, 1992; now U.S. Pat. No. 5,246,661, I have disclosed alloys developed for severe abrasion and corrosion service such as encountered in wet process phosphoric acid reactors. Abrasion and corrosion degradation in such reactors is so severe that pumps made of prior art alloys typically need to be replaced every two to six months due to metal surface losses of the order of a half to three quarters of an inch. However, there are other corrosion applications in which longer service life may be expected due to somewhat less severe abrasion. In those instances surface metal loss rates may be low, but failure of the metallic parts may take place due to rapid intergranular attack along the matrix grain boundaries of alloys containing precipitated chromium carbides.